News & Blogs
How does a shunt trip work to trip a circuit breaker?
A shunt trip device is an optional accessory in a circuit breaker that mechanically trips the breaker when power is applied to the shunt trip terminals. The power for the shunt trip does not come from within the breaker, so it must be supplied from an external source. Some circuit breakers allow field installlation of a shunt trip kit, however others require factory installation when the breaker is ordered. Check the specific breaker type for available ac and dc shunt trip voltage ratings and fo
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3rd Jul 2019
How to Calculate the Required Capacity kVA Rating or Amperage Capacity for Single and Three Phase Transformers?
To determine kVA you must have at least two pieces of information:the load line-to-line voltage (V)the maximum load phase current (I)Single Phase Transformers: kVA = (V * I) /1000Three Phase Transformers: kVA = (V * I * 1.732) / 1000where 1.732 is the simple numerical value for the square root of 3 (1.7320508...)Then round up to the next standard 3ph kVA rating as found in Section 14 of SquareD/Schneider Electric Catalog, Digest 177.Single Phase Transformer Example: V = 240, I = 175; Therefore:
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2nd Jul 2019
How do I select the proper Buck & Boost Transformer to go from 208V to 240V, or from 240V to 208V?
Use Buck & Boost catalog 7414CT0001, Buck & Boost `slide rule` 7414SP9901, the On-Line Buck & Boost Transformer Calculator at: http://buckboostcalculator.com/index.cfm, or...1. If the load is single phase:A. Multiply 32 volts times the load amperage needed to obtain VA of Buck & Boost TransformerB. Choose a `SV46` Transformer of next larger standard size above the VA obtained in A.Example: if load is 11 amperes, multiply 11 x 32 = 352VA, choose catalog number 500SV46BC. Connect using wiring dia
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2nd Jul 2019
What are the arc fault breaker for NQOD panels?
15 and 20 amp 1 pole breakers QO115AFI and QO120AFI QOB115AFI QOB120AFI QO115VHAFI QO120VHAFI
2nd Jul 2019
Does the smoke alarm circuit in a bedroom need to be AFI protected?
Yes. They fall under the category of bedroom outlets. The way the 2002 NEC Art. 210.12(B) is worded, all bedroom outlets (including the smoke detector) must be supplied by an AFCI protected circuit. See text below:NEC 210-12 (B) Dwelling Unit Bedrooms. ``All branch circuits that supply 125-volt, single-phase, 15- and 20-ampere outlets installed in dwelling unit bedrooms shall be protected by an arc-fault circuit interrupter listed to provide protection of the entire branch circuit.``
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2nd Jul 2019